| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <36272d4a-eb95-4842-b171-ad6ec39a7631@gmail.com>
Date: Mon, 19 Aug 2024 17:41:35 +0200
From: Michal Rostecki <vadorovsky@...il.com>
Cc: Miguel Ojeda <ojeda@...nel.org>, Alex Gaynor <alex.gaynor@...il.com>,
Wedson Almeida Filho <wedsonaf@...il.com>, Boqun Feng
<boqun.feng@...il.com>, Gary Guo <gary@...yguo.net>,
BjΓΆrn Roy Baron <bjorn3_gh@...tonmail.com>,
Benno Lossin <benno.lossin@...ton.me>,
Andreas Hindborg <a.hindborg@...sung.com>, Alice Ryhl
<aliceryhl@...gle.com>, Brendan Higgins <brendan.higgins@...ux.dev>,
David Gow <davidgow@...gle.com>, Rae Moar <rmoar@...gle.com>,
FUJITA Tomonori <fujita.tomonori@...il.com>, Trevor Gross
<tmgross@...ch.edu>, Nathan Chancellor <nathan@...nel.org>,
Nick Desaulniers <ndesaulniers@...gle.com>, Bill Wendling
<morbo@...gle.com>, Justin Stitt <justinstitt@...gle.com>,
Martin Rodriguez Reboredo <yakoyoku@...il.com>, Finn Behrens
<me@...enk.dev>, Manmohan Shukla <manmshuk@...il.com>,
Valentin Obst <kernel@...entinobst.de>,
Yutaro Ohno <yutaro.ono.418@...il.com>, Asahi Lina <lina@...hilina.net>,
Danilo Krummrich <dakr@...hat.com>, Tiago Lam <tiagolam@...il.com>,
Charalampos Mitrodimas <charmitro@...teo.net>, Tejun Heo <tj@...nel.org>,
Roland Xu <mu001999@...look.com>, rust-for-linux@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-kselftest@...r.kernel.org,
kunit-dev@...glegroups.com, netdev@...r.kernel.org, llvm@...ts.linux.dev
Subject: Re: [PATCH RESEND v5] rust: str: Use `core::CStr`, remove the custom
`CStr` implementation
On 8/19/24 17:36, Michal Rostecki wrote:
> From: Michal Rostecki <vadorovsky@...il.com>
>
> `CStr` became a part of `core` library in Rust 1.75. This change replaces
> the custom `CStr` implementation with the one from `core`.
>
> `core::CStr` behaves generally the same as the removed implementation,
> with the following differences:
>
> - It does not implement `Display`.
> - It does not provide `from_bytes_with_nul_unchecked_mut` method.
> - It has `as_ptr()` method instead of `as_char_ptr()`, which also returns
> `*const c_char`.
>
> The first two differences are handled by providing the `CStrExt` trait,
> with `display()` and `from_bytes_with_nul_unchecked_mut()` methods.
> `display()` returns a `CStrDisplay` wrapper, with a custom `Display`
> implementation.
>
> `DerefMut` implementation for `CString` is removed here, as it's not
> being used anywhere.
>
> Signed-off-by: Michal Rostecki <vadorovsky@...il.com>
> ---
> rust/kernel/error.rs | 7 +-
> rust/kernel/kunit.rs | 18 +-
> rust/kernel/net/phy.rs | 2 +-
> rust/kernel/prelude.rs | 4 +-
> rust/kernel/str.rs | 465 ++++++------------------------------
> rust/kernel/sync/condvar.rs | 5 +-
> rust/kernel/sync/lock.rs | 6 +-
> rust/kernel/workqueue.rs | 2 +-
> scripts/rustdoc_test_gen.rs | 4 +-
> 9 files changed, 93 insertions(+), 420 deletions(-)
>
> diff --git a/rust/kernel/error.rs b/rust/kernel/error.rs
> index 6f1587a2524e..6a2bb11ac09c 100644
> --- a/rust/kernel/error.rs
> +++ b/rust/kernel/error.rs
> @@ -4,10 +4,11 @@
> //!
> //! C header: [`include/uapi/asm-generic/errno-base.h`](srctree/include/uapi/asm-generic/errno-base.h)
>
> -use crate::{alloc::AllocError, str::CStr};
> +use crate::alloc::AllocError;
>
> use alloc::alloc::LayoutError;
>
> +use core::ffi::CStr;
> use core::fmt;
> use core::num::TryFromIntError;
> use core::str::Utf8Error;
> @@ -151,7 +152,7 @@ pub fn name(&self) -> Option<&'static CStr> {
> None
> } else {
> // SAFETY: The string returned by `errname` is static and `NUL`-terminated.
> - Some(unsafe { CStr::from_char_ptr(ptr) })
> + Some(unsafe { CStr::from_ptr(ptr) })
> }
> }
>
> @@ -173,7 +174,7 @@ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
> None => f.debug_tuple("Error").field(&-self.0).finish(),
> // SAFETY: These strings are ASCII-only.
> Some(name) => f
> - .debug_tuple(unsafe { core::str::from_utf8_unchecked(name) })
> + .debug_tuple(unsafe { core::str::from_utf8_unchecked(name.to_bytes()) })
> .finish(),
> }
> }
> diff --git a/rust/kernel/kunit.rs b/rust/kernel/kunit.rs
> index 0ba77276ae7e..79a50ab59af0 100644
> --- a/rust/kernel/kunit.rs
> +++ b/rust/kernel/kunit.rs
> @@ -56,13 +56,15 @@ macro_rules! kunit_assert {
> break 'out;
> }
>
> - static FILE: &'static $crate::str::CStr = $crate::c_str!($file);
> + static FILE: &'static core::ffi::CStr = $file;
> static LINE: i32 = core::line!() as i32 - $diff;
> - static CONDITION: &'static $crate::str::CStr = $crate::c_str!(stringify!($condition));
> + static CONDITION: &'static core::ffi::CStr = $crate::c_str!(stringify!($condition));
>
> // SAFETY: FFI call without safety requirements.
> let kunit_test = unsafe { $crate::bindings::kunit_get_current_test() };
> if kunit_test.is_null() {
> + use kernel::str::CStrExt;
> +
> // The assertion failed but this task is not running a KUnit test, so we cannot call
> // KUnit, but at least print an error to the kernel log. This may happen if this
> // macro is called from an spawned thread in a test (see
> @@ -71,11 +73,13 @@ macro_rules! kunit_assert {
> //
> // This mimics KUnit's failed assertion format.
> $crate::kunit::err(format_args!(
> - " # {}: ASSERTION FAILED at {FILE}:{LINE}\n",
> - $name
> + " # {}: ASSERTION FAILED at {}:{LINE}\n",
> + $name.display(),
> + FILE.display(),
> ));
> $crate::kunit::err(format_args!(
> - " Expected {CONDITION} to be true, but is false\n"
> + " Expected {} to be true, but is false\n",
> + CONDITION.display(),
> ));
> $crate::kunit::err(format_args!(
> " Failure not reported to KUnit since this is a non-KUnit task\n"
> @@ -98,12 +102,12 @@ unsafe impl Sync for Location {}
> unsafe impl Sync for UnaryAssert {}
>
> static LOCATION: Location = Location($crate::bindings::kunit_loc {
> - file: FILE.as_char_ptr(),
> + file: FILE.as_ptr(),
> line: LINE,
> });
> static ASSERTION: UnaryAssert = UnaryAssert($crate::bindings::kunit_unary_assert {
> assert: $crate::bindings::kunit_assert {},
> - condition: CONDITION.as_char_ptr(),
> + condition: CONDITION.as_ptr(),
> expected_true: true,
> });
>
> diff --git a/rust/kernel/net/phy.rs b/rust/kernel/net/phy.rs
> index fd40b703d224..19f45922ec42 100644
> --- a/rust/kernel/net/phy.rs
> +++ b/rust/kernel/net/phy.rs
> @@ -502,7 +502,7 @@ unsafe impl Sync for DriverVTable {}
> pub const fn create_phy_driver<T: Driver>() -> DriverVTable {
> // INVARIANT: All the fields of `struct phy_driver` are initialized properly.
> DriverVTable(Opaque::new(bindings::phy_driver {
> - name: T::NAME.as_char_ptr().cast_mut(),
> + name: T::NAME.as_ptr().cast_mut(),
> flags: T::FLAGS,
> phy_id: T::PHY_DEVICE_ID.id,
> phy_id_mask: T::PHY_DEVICE_ID.mask_as_int(),
> diff --git a/rust/kernel/prelude.rs b/rust/kernel/prelude.rs
> index b37a0b3180fb..b0969ca78f10 100644
> --- a/rust/kernel/prelude.rs
> +++ b/rust/kernel/prelude.rs
> @@ -12,7 +12,7 @@
> //! ```
>
> #[doc(no_inline)]
> -pub use core::pin::Pin;
> +pub use core::{ffi::CStr, pin::Pin};
>
> pub use crate::alloc::{box_ext::BoxExt, flags::*, vec_ext::VecExt};
>
> @@ -35,7 +35,7 @@
>
> pub use super::error::{code::*, Error, Result};
>
> -pub use super::{str::CStr, ThisModule};
> +pub use super::ThisModule;
>
> pub use super::init::{InPlaceInit, Init, PinInit};
>
> diff --git a/rust/kernel/str.rs b/rust/kernel/str.rs
> index bb8d4f41475b..97a298a44b96 100644
> --- a/rust/kernel/str.rs
> +++ b/rust/kernel/str.rs
> @@ -4,8 +4,9 @@
>
> use crate::alloc::{flags::*, vec_ext::VecExt, AllocError};
> use alloc::vec::Vec;
> +use core::ffi::CStr;
> use core::fmt::{self, Write};
> -use core::ops::{self, Deref, DerefMut, Index};
> +use core::ops::Deref;
>
> use crate::error::{code::*, Error};
>
> @@ -41,11 +42,11 @@ impl fmt::Display for BStr {
> /// # use kernel::{fmt, b_str, str::{BStr, CString}};
> /// let ascii = b_str!("Hello, BStr!");
> /// let s = CString::try_from_fmt(fmt!("{}", ascii)).unwrap();
> - /// assert_eq!(s.as_bytes(), "Hello, BStr!".as_bytes());
> + /// assert_eq!(s.to_bytes(), "Hello, BStr!".as_bytes());
> ///
> /// let non_ascii = b_str!("π¦");
> /// let s = CString::try_from_fmt(fmt!("{}", non_ascii)).unwrap();
> - /// assert_eq!(s.as_bytes(), "\\xf0\\x9f\\xa6\\x80".as_bytes());
> + /// assert_eq!(s.to_bytes(), "\\xf0\\x9f\\xa6\\x80".as_bytes());
> /// ```
> fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
> for &b in &self.0 {
> @@ -72,11 +73,11 @@ impl fmt::Debug for BStr {
> /// // Embedded double quotes are escaped.
> /// let ascii = b_str!("Hello, \"BStr\"!");
> /// let s = CString::try_from_fmt(fmt!("{:?}", ascii)).unwrap();
> - /// assert_eq!(s.as_bytes(), "\"Hello, \\\"BStr\\\"!\"".as_bytes());
> + /// assert_eq!(s.to_bytes(), "\"Hello, \\\"BStr\\\"!\"".as_bytes());
> ///
> /// let non_ascii = b_str!("πΊ");
> /// let s = CString::try_from_fmt(fmt!("{:?}", non_ascii)).unwrap();
> - /// assert_eq!(s.as_bytes(), "\"\\xf0\\x9f\\x98\\xba\"".as_bytes());
> + /// assert_eq!(s.to_bytes(), "\"\\xf0\\x9f\\x98\\xba\"".as_bytes());
> /// ```
> fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
> f.write_char('"')?;
> @@ -128,271 +129,29 @@ macro_rules! b_str {
> }};
> }
>
> -/// Possible errors when using conversion functions in [`CStr`].
> -#[derive(Debug, Clone, Copy)]
> -pub enum CStrConvertError {
> - /// Supplied bytes contain an interior `NUL`.
> - InteriorNul,
> +/// Wrapper around [`CStr`] which implements [`Display`](core::fmt::Display).
> +pub struct CStrDisplay<'a>(&'a CStr);
>
> - /// Supplied bytes are not terminated by `NUL`.
> - NotNulTerminated,
> -}
> -
> -impl From<CStrConvertError> for Error {
> - #[inline]
> - fn from(_: CStrConvertError) -> Error {
> - EINVAL
> - }
> -}
> -
> -/// A string that is guaranteed to have exactly one `NUL` byte, which is at the
> -/// end.
> -///
> -/// Used for interoperability with kernel APIs that take C strings.
> -#[repr(transparent)]
> -pub struct CStr([u8]);
> -
> -impl CStr {
> - /// Returns the length of this string excluding `NUL`.
> - #[inline]
> - pub const fn len(&self) -> usize {
> - self.len_with_nul() - 1
> - }
> -
> - /// Returns the length of this string with `NUL`.
> - #[inline]
> - pub const fn len_with_nul(&self) -> usize {
> - // SAFETY: This is one of the invariant of `CStr`.
> - // We add a `unreachable_unchecked` here to hint the optimizer that
> - // the value returned from this function is non-zero.
> - if self.0.is_empty() {
> - unsafe { core::hint::unreachable_unchecked() };
> - }
> - self.0.len()
> - }
> -
> - /// Returns `true` if the string only includes `NUL`.
> - #[inline]
> - pub const fn is_empty(&self) -> bool {
> - self.len() == 0
> - }
> -
> - /// Wraps a raw C string pointer.
> - ///
> - /// # Safety
> - ///
> - /// `ptr` must be a valid pointer to a `NUL`-terminated C string, and it must
> - /// last at least `'a`. When `CStr` is alive, the memory pointed by `ptr`
> - /// must not be mutated.
> - #[inline]
> - pub unsafe fn from_char_ptr<'a>(ptr: *const core::ffi::c_char) -> &'a Self {
> - // SAFETY: The safety precondition guarantees `ptr` is a valid pointer
> - // to a `NUL`-terminated C string.
> - let len = unsafe { bindings::strlen(ptr) } + 1;
> - // SAFETY: Lifetime guaranteed by the safety precondition.
> - let bytes = unsafe { core::slice::from_raw_parts(ptr as _, len as _) };
> - // SAFETY: As `len` is returned by `strlen`, `bytes` does not contain interior `NUL`.
> - // As we have added 1 to `len`, the last byte is known to be `NUL`.
> - unsafe { Self::from_bytes_with_nul_unchecked(bytes) }
> - }
> -
> - /// Creates a [`CStr`] from a `[u8]`.
> - ///
> - /// The provided slice must be `NUL`-terminated, does not contain any
> - /// interior `NUL` bytes.
> - pub const fn from_bytes_with_nul(bytes: &[u8]) -> Result<&Self, CStrConvertError> {
> - if bytes.is_empty() {
> - return Err(CStrConvertError::NotNulTerminated);
> - }
> - if bytes[bytes.len() - 1] != 0 {
> - return Err(CStrConvertError::NotNulTerminated);
> - }
> - let mut i = 0;
> - // `i + 1 < bytes.len()` allows LLVM to optimize away bounds checking,
> - // while it couldn't optimize away bounds checks for `i < bytes.len() - 1`.
> - while i + 1 < bytes.len() {
> - if bytes[i] == 0 {
> - return Err(CStrConvertError::InteriorNul);
> - }
> - i += 1;
> - }
> - // SAFETY: We just checked that all properties hold.
> - Ok(unsafe { Self::from_bytes_with_nul_unchecked(bytes) })
> - }
> -
> - /// Creates a [`CStr`] from a `[u8]` without performing any additional
> - /// checks.
> - ///
> - /// # Safety
> - ///
> - /// `bytes` *must* end with a `NUL` byte, and should only have a single
> - /// `NUL` byte (or the string will be truncated).
> - #[inline]
> - pub const unsafe fn from_bytes_with_nul_unchecked(bytes: &[u8]) -> &CStr {
> - // SAFETY: Properties of `bytes` guaranteed by the safety precondition.
> - unsafe { core::mem::transmute(bytes) }
> - }
> -
> - /// Creates a mutable [`CStr`] from a `[u8]` without performing any
> - /// additional checks.
> - ///
> - /// # Safety
> - ///
> - /// `bytes` *must* end with a `NUL` byte, and should only have a single
> - /// `NUL` byte (or the string will be truncated).
> - #[inline]
> - pub unsafe fn from_bytes_with_nul_unchecked_mut(bytes: &mut [u8]) -> &mut CStr {
> - // SAFETY: Properties of `bytes` guaranteed by the safety precondition.
> - unsafe { &mut *(bytes as *mut [u8] as *mut CStr) }
> - }
> -
> - /// Returns a C pointer to the string.
> - #[inline]
> - pub const fn as_char_ptr(&self) -> *const core::ffi::c_char {
> - self.0.as_ptr() as _
> - }
> -
> - /// Convert the string to a byte slice without the trailing `NUL` byte.
> - #[inline]
> - pub fn as_bytes(&self) -> &[u8] {
> - &self.0[..self.len()]
> - }
> -
> - /// Convert the string to a byte slice containing the trailing `NUL` byte.
> - #[inline]
> - pub const fn as_bytes_with_nul(&self) -> &[u8] {
> - &self.0
> - }
> -
> - /// Yields a [`&str`] slice if the [`CStr`] contains valid UTF-8.
> - ///
> - /// If the contents of the [`CStr`] are valid UTF-8 data, this
> - /// function will return the corresponding [`&str`] slice. Otherwise,
> - /// it will return an error with details of where UTF-8 validation failed.
> - ///
> - /// # Examples
> - ///
> - /// ```
> - /// # use kernel::str::CStr;
> - /// let cstr = CStr::from_bytes_with_nul(b"foo\0").unwrap();
> - /// assert_eq!(cstr.to_str(), Ok("foo"));
> - /// ```
> - #[inline]
> - pub fn to_str(&self) -> Result<&str, core::str::Utf8Error> {
> - core::str::from_utf8(self.as_bytes())
> - }
> -
> - /// Unsafely convert this [`CStr`] into a [`&str`], without checking for
> - /// valid UTF-8.
> - ///
> - /// # Safety
> - ///
> - /// The contents must be valid UTF-8.
> +impl fmt::Display for CStrDisplay<'_> {
> + /// Formats printable ASCII characters, escaping the rest.
> ///
> /// # Examples
> ///
> /// ```
> - /// # use kernel::c_str;
> - /// # use kernel::str::CStr;
> - /// let bar = c_str!("γ");
> - /// // SAFETY: String literals are guaranteed to be valid UTF-8
> - /// // by the Rust compiler.
> - /// assert_eq!(unsafe { bar.as_str_unchecked() }, "γ");
> - /// ```
> - #[inline]
> - pub unsafe fn as_str_unchecked(&self) -> &str {
> - unsafe { core::str::from_utf8_unchecked(self.as_bytes()) }
> - }
> -
> - /// Convert this [`CStr`] into a [`CString`] by allocating memory and
> - /// copying over the string data.
> - pub fn to_cstring(&self) -> Result<CString, AllocError> {
> - CString::try_from(self)
> - }
> -
> - /// Converts this [`CStr`] to its ASCII lower case equivalent in-place.
> - ///
> - /// ASCII letters 'A' to 'Z' are mapped to 'a' to 'z',
> - /// but non-ASCII letters are unchanged.
> - ///
> - /// To return a new lowercased value without modifying the existing one, use
> - /// [`to_ascii_lowercase()`].
> - ///
> - /// [`to_ascii_lowercase()`]: #method.to_ascii_lowercase
> - pub fn make_ascii_lowercase(&mut self) {
> - // INVARIANT: This doesn't introduce or remove NUL bytes in the C
> - // string.
> - self.0.make_ascii_lowercase();
> - }
> -
> - /// Converts this [`CStr`] to its ASCII upper case equivalent in-place.
> - ///
> - /// ASCII letters 'a' to 'z' are mapped to 'A' to 'Z',
> - /// but non-ASCII letters are unchanged.
> - ///
> - /// To return a new uppercased value without modifying the existing one, use
> - /// [`to_ascii_uppercase()`].
> - ///
> - /// [`to_ascii_uppercase()`]: #method.to_ascii_uppercase
> - pub fn make_ascii_uppercase(&mut self) {
> - // INVARIANT: This doesn't introduce or remove NUL bytes in the C
> - // string.
> - self.0.make_ascii_uppercase();
> - }
> -
> - /// Returns a copy of this [`CString`] where each character is mapped to its
> - /// ASCII lower case equivalent.
> - ///
> - /// ASCII letters 'A' to 'Z' are mapped to 'a' to 'z',
> - /// but non-ASCII letters are unchanged.
> - ///
> - /// To lowercase the value in-place, use [`make_ascii_lowercase`].
> - ///
> - /// [`make_ascii_lowercase`]: str::make_ascii_lowercase
> - pub fn to_ascii_lowercase(&self) -> Result<CString, AllocError> {
> - let mut s = self.to_cstring()?;
> -
> - s.make_ascii_lowercase();
> -
> - Ok(s)
> - }
> -
> - /// Returns a copy of this [`CString`] where each character is mapped to its
> - /// ASCII upper case equivalent.
> - ///
> - /// ASCII letters 'a' to 'z' are mapped to 'A' to 'Z',
> - /// but non-ASCII letters are unchanged.
> - ///
> - /// To uppercase the value in-place, use [`make_ascii_uppercase`].
> - ///
> - /// [`make_ascii_uppercase`]: str::make_ascii_uppercase
> - pub fn to_ascii_uppercase(&self) -> Result<CString, AllocError> {
> - let mut s = self.to_cstring()?;
> -
> - s.make_ascii_uppercase();
> -
> - Ok(s)
> - }
> -}
> -
> -impl fmt::Display for CStr {
> - /// Formats printable ASCII characters, escaping the rest.
> - ///
> - /// ```
> + /// # use core::ffi::CStr;
> /// # use kernel::c_str;
> /// # use kernel::fmt;
> - /// # use kernel::str::CStr;
> - /// # use kernel::str::CString;
> - /// let penguin = c_str!("π§");
> - /// let s = CString::try_from_fmt(fmt!("{}", penguin)).unwrap();
> - /// assert_eq!(s.as_bytes_with_nul(), "\\xf0\\x9f\\x90\\xa7\0".as_bytes());
> - ///
> - /// let ascii = c_str!("so \"cool\"");
> - /// let s = CString::try_from_fmt(fmt!("{}", ascii)).unwrap();
> - /// assert_eq!(s.as_bytes_with_nul(), "so \"cool\"\0".as_bytes());
> + /// # use kernel::str::{CStrExt, CString};
> + /// let penguin = c"π§";
> + /// let s = CString::try_from_fmt(fmt!("{}", penguin.display())).unwrap();
> + /// assert_eq!(s.to_bytes_with_nul(), "\\xf0\\x9f\\x90\\xa7\0".as_bytes());
> + ///
> + /// let ascii = c"so \"cool\"";
> + /// let s = CString::try_from_fmt(fmt!("{}", ascii.display())).unwrap();
> + /// assert_eq!(s.to_bytes_with_nul(), "so \"cool\"\0".as_bytes());
> /// ```
> fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
> - for &c in self.as_bytes() {
> + for &c in self.0.to_bytes() {
> if (0x20..0x7f).contains(&c) {
> // Printable character.
> f.write_char(c as char)?;
> @@ -404,116 +163,70 @@ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
> }
> }
>
> -impl fmt::Debug for CStr {
> - /// Formats printable ASCII characters with a double quote on either end, escaping the rest.
> +/// Extensions to [`CStr`].
> +pub trait CStrExt {
> + /// Returns an object that implements [`Display`](core::fmt::Display) for
> + /// safely printing a [`CStr`] that may contain non-ASCII data, which are
> + /// escaped.
> + ///
> + /// # Examples
> ///
> /// ```
> + /// # use core::ffi::CStr;
> /// # use kernel::c_str;
> /// # use kernel::fmt;
> - /// # use kernel::str::CStr;
> - /// # use kernel::str::CString;
> - /// let penguin = c_str!("π§");
> - /// let s = CString::try_from_fmt(fmt!("{:?}", penguin)).unwrap();
> - /// assert_eq!(s.as_bytes_with_nul(), "\"\\xf0\\x9f\\x90\\xa7\"\0".as_bytes());
> - ///
> - /// // Embedded double quotes are escaped.
> - /// let ascii = c_str!("so \"cool\"");
> - /// let s = CString::try_from_fmt(fmt!("{:?}", ascii)).unwrap();
> - /// assert_eq!(s.as_bytes_with_nul(), "\"so \\\"cool\\\"\"\0".as_bytes());
> + /// # use kernel::str::{CStrExt, CString};
> + /// let penguin = c"π§";
> + /// let s = CString::try_from_fmt(fmt!("{}", penguin.display())).unwrap();
> + /// assert_eq!(s.to_bytes_with_nul(), "\\xf0\\x9f\\x90\\xa7\0".as_bytes());
> + ///
> + /// let ascii = c"so \"cool\"";
> + /// let s = CString::try_from_fmt(fmt!("{}", ascii.display())).unwrap();
> + /// assert_eq!(s.to_bytes_with_nul(), "so \"cool\"\0".as_bytes());
> /// ```
> - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
> - f.write_str("\"")?;
> - for &c in self.as_bytes() {
> - match c {
> - // Printable characters.
> - b'\"' => f.write_str("\\\"")?,
> - 0x20..=0x7e => f.write_char(c as char)?,
> - _ => write!(f, "\\x{:02x}", c)?,
> - }
> - }
> - f.write_str("\"")
> - }
> -}
> -
> -impl AsRef<BStr> for CStr {
> - #[inline]
> - fn as_ref(&self) -> &BStr {
> - BStr::from_bytes(self.as_bytes())
> - }
> -}
> -
> -impl Deref for CStr {
> - type Target = BStr;
> -
> - #[inline]
> - fn deref(&self) -> &Self::Target {
> - self.as_ref()
> - }
> -}
> -
> -impl Index<ops::RangeFrom<usize>> for CStr {
> - type Output = CStr;
> + fn display(&self) -> CStrDisplay<'_>;
>
> - #[inline]
> - fn index(&self, index: ops::RangeFrom<usize>) -> &Self::Output {
> - // Delegate bounds checking to slice.
> - // Assign to _ to mute clippy's unnecessary operation warning.
> - let _ = &self.as_bytes()[index.start..];
> - // SAFETY: We just checked the bounds.
> - unsafe { Self::from_bytes_with_nul_unchecked(&self.0[index.start..]) }
> - }
> + /// Creates a mutable [`CStr`] from a `[u8]` without performing any
> + /// additional checks.
> + ///
> + /// # Safety
> + ///
> + /// `bytes` *must* end with a `NUL` byte, and should only have a single
> + /// `NUL` byte (or the string will be truncated).
> + unsafe fn from_bytes_with_nul_unchecked_mut(bytes: &mut [u8]) -> &mut Self;
> }
>
> -impl Index<ops::RangeFull> for CStr {
> - type Output = CStr;
> -
> - #[inline]
> - fn index(&self, _index: ops::RangeFull) -> &Self::Output {
> - self
> +impl CStrExt for CStr {
> + fn display(&self) -> CStrDisplay<'_> {
> + CStrDisplay(self)
> }
> -}
>
> -mod private {
> - use core::ops;
> -
> - // Marker trait for index types that can be forward to `BStr`.
> - pub trait CStrIndex {}
> -
> - impl CStrIndex for usize {}
> - impl CStrIndex for ops::Range<usize> {}
> - impl CStrIndex for ops::RangeInclusive<usize> {}
> - impl CStrIndex for ops::RangeToInclusive<usize> {}
> -}
> -
> -impl<Idx> Index<Idx> for CStr
> -where
> - Idx: private::CStrIndex,
> - BStr: Index<Idx>,
> -{
> - type Output = <BStr as Index<Idx>>::Output;
> -
> - #[inline]
> - fn index(&self, index: Idx) -> &Self::Output {
> - &self.as_ref()[index]
> + unsafe fn from_bytes_with_nul_unchecked_mut(bytes: &mut [u8]) -> &mut Self {
> + // SAFETY: Properties of `bytes` guaranteed by the safety precondition.
> + unsafe { &mut *(bytes as *mut [u8] as *mut CStr) }
> }
> }
>
> /// Creates a new [`CStr`] from a string literal.
> ///
> -/// The string literal should not contain any `NUL` bytes.
> +/// This macro is not needed when C-string literals (`c"hello"` syntax) can be
> +/// used directly, but can be used when a C-string version of a standard string
> +/// literal is required (often when working with macros).
> +///
> +/// The string should not contain any `NUL` bytes.
> ///
> /// # Examples
> ///
> /// ```
> +/// # use core::ffi::CStr;
> /// # use kernel::c_str;
> -/// # use kernel::str::CStr;
> -/// const MY_CSTR: &CStr = c_str!("My awesome CStr!");
> +/// const MY_CSTR: &CStr = c_str!(stringify!(5));
> /// ```
> #[macro_export]
> macro_rules! c_str {
> ($str:expr) => {{
> const S: &str = concat!($str, "\0");
> - const C: &$crate::str::CStr = match $crate::str::CStr::from_bytes_with_nul(S.as_bytes()) {
> + const C: &core::ffi::CStr = match core::ffi::CStr::from_bytes_with_nul(S.as_bytes()) {
> Ok(v) => v,
> Err(_) => panic!("string contains interior NUL"),
> };
> @@ -540,40 +253,16 @@ mod tests {
> \\xe0\\xe1\\xe2\\xe3\\xe4\\xe5\\xe6\\xe7\\xe8\\xe9\\xea\\xeb\\xec\\xed\\xee\\xef\
> \\xf0\\xf1\\xf2\\xf3\\xf4\\xf5\\xf6\\xf7\\xf8\\xf9\\xfa\\xfb\\xfc\\xfd\\xfe\\xff";
>
> - #[test]
> - fn test_cstr_to_str() {
> - let good_bytes = b"\xf0\x9f\xa6\x80\0";
> - let checked_cstr = CStr::from_bytes_with_nul(good_bytes).unwrap();
> - let checked_str = checked_cstr.to_str().unwrap();
> - assert_eq!(checked_str, "π¦");
> - }
> -
> - #[test]
> - #[should_panic]
> - fn test_cstr_to_str_panic() {
> - let bad_bytes = b"\xc3\x28\0";
> - let checked_cstr = CStr::from_bytes_with_nul(bad_bytes).unwrap();
> - checked_cstr.to_str().unwrap();
> - }
> -
> - #[test]
> - fn test_cstr_as_str_unchecked() {
> - let good_bytes = b"\xf0\x9f\x90\xA7\0";
> - let checked_cstr = CStr::from_bytes_with_nul(good_bytes).unwrap();
> - let unchecked_str = unsafe { checked_cstr.as_str_unchecked() };
> - assert_eq!(unchecked_str, "π§");
> - }
> -
> #[test]
> fn test_cstr_display() {
> let hello_world = CStr::from_bytes_with_nul(b"hello, world!\0").unwrap();
> - assert_eq!(format!("{}", hello_world), "hello, world!");
> + assert_eq!(format!("{}", hello_world.display()), "hello, world!");
> let non_printables = CStr::from_bytes_with_nul(b"\x01\x09\x0a\0").unwrap();
> - assert_eq!(format!("{}", non_printables), "\\x01\\x09\\x0a");
> + assert_eq!(format!("{}", non_printables.display()), "\\x01\\x09\\x0a");
> let non_ascii = CStr::from_bytes_with_nul(b"d\xe9j\xe0 vu\0").unwrap();
> - assert_eq!(format!("{}", non_ascii), "d\\xe9j\\xe0 vu");
> + assert_eq!(format!("{}", non_ascii.display()), "d\\xe9j\\xe0 vu");
> let good_bytes = CStr::from_bytes_with_nul(b"\xf0\x9f\xa6\x80\0").unwrap();
> - assert_eq!(format!("{}", good_bytes), "\\xf0\\x9f\\xa6\\x80");
> + assert_eq!(format!("{}", good_bytes.display()), "\\xf0\\x9f\\xa6\\x80");
> }
>
> #[test]
> @@ -584,19 +273,7 @@ fn test_cstr_display_all_bytes() {
> bytes[i as usize] = i.wrapping_add(1);
> }
> let cstr = CStr::from_bytes_with_nul(&bytes).unwrap();
> - assert_eq!(format!("{}", cstr), ALL_ASCII_CHARS);
> - }
> -
> - #[test]
> - fn test_cstr_debug() {
> - let hello_world = CStr::from_bytes_with_nul(b"hello, world!\0").unwrap();
> - assert_eq!(format!("{:?}", hello_world), "\"hello, world!\"");
> - let non_printables = CStr::from_bytes_with_nul(b"\x01\x09\x0a\0").unwrap();
> - assert_eq!(format!("{:?}", non_printables), "\"\\x01\\x09\\x0a\"");
> - let non_ascii = CStr::from_bytes_with_nul(b"d\xe9j\xe0 vu\0").unwrap();
> - assert_eq!(format!("{:?}", non_ascii), "\"d\\xe9j\\xe0 vu\"");
> - let good_bytes = CStr::from_bytes_with_nul(b"\xf0\x9f\xa6\x80\0").unwrap();
> - assert_eq!(format!("{:?}", good_bytes), "\"\\xf0\\x9f\\xa6\\x80\"");
> + assert_eq!(format!("{}", cstr.display()), ALL_ASCII_CHARS);
> }
>
> #[test]
> @@ -779,11 +456,11 @@ fn write_str(&mut self, s: &str) -> fmt::Result {
> /// use kernel::{str::CString, fmt};
> ///
> /// let s = CString::try_from_fmt(fmt!("{}{}{}", "abc", 10, 20)).unwrap();
> -/// assert_eq!(s.as_bytes_with_nul(), "abc1020\0".as_bytes());
> +/// assert_eq!(s.to_bytes_with_nul(), "abc1020\0".as_bytes());
> ///
> /// let tmp = "testing";
> /// let s = CString::try_from_fmt(fmt!("{tmp}{}", 123)).unwrap();
> -/// assert_eq!(s.as_bytes_with_nul(), "testing123\0".as_bytes());
> +/// assert_eq!(s.to_bytes_with_nul(), "testing123\0".as_bytes());
> ///
> /// // This fails because it has an embedded `NUL` byte.
> /// let s = CString::try_from_fmt(fmt!("a\0b{}", 123));
> @@ -838,21 +515,13 @@ fn deref(&self) -> &Self::Target {
> }
> }
>
> -impl DerefMut for CString {
> - fn deref_mut(&mut self) -> &mut Self::Target {
> - // SAFETY: A `CString` is always NUL-terminated and contains no other
> - // NUL bytes.
> - unsafe { CStr::from_bytes_with_nul_unchecked_mut(self.buf.as_mut_slice()) }
> - }
> -}
> -
> impl<'a> TryFrom<&'a CStr> for CString {
> type Error = AllocError;
>
> fn try_from(cstr: &'a CStr) -> Result<CString, AllocError> {
> let mut buf = Vec::new();
>
> - <Vec<_> as VecExt<_>>::extend_from_slice(&mut buf, cstr.as_bytes_with_nul(), GFP_KERNEL)
> + <Vec<_> as VecExt<_>>::extend_from_slice(&mut buf, cstr.to_bytes_with_nul(), GFP_KERNEL)
> .map_err(|_| AllocError)?;
>
> // INVARIANT: The `CStr` and `CString` types have the same invariants for
> diff --git a/rust/kernel/sync/condvar.rs b/rust/kernel/sync/condvar.rs
> index 2b306afbe56d..16d1a1cb8d00 100644
> --- a/rust/kernel/sync/condvar.rs
> +++ b/rust/kernel/sync/condvar.rs
> @@ -9,12 +9,11 @@
> use crate::{
> init::PinInit,
> pin_init,
> - str::CStr,
> task::{MAX_SCHEDULE_TIMEOUT, TASK_INTERRUPTIBLE, TASK_NORMAL, TASK_UNINTERRUPTIBLE},
> time::Jiffies,
> types::Opaque,
> };
> -use core::ffi::{c_int, c_long};
> +use core::ffi::{c_int, c_long, CStr};
> use core::marker::PhantomPinned;
> use core::ptr;
> use macros::pin_data;
> @@ -108,7 +107,7 @@ pub fn new(name: &'static CStr, key: &'static LockClassKey) -> impl PinInit<Self
> // SAFETY: `slot` is valid while the closure is called and both `name` and `key` have
> // static lifetimes so they live indefinitely.
> wait_queue_head <- Opaque::ffi_init(|slot| unsafe {
> - bindings::__init_waitqueue_head(slot, name.as_char_ptr(), key.as_ptr())
> + bindings::__init_waitqueue_head(slot, name.as_ptr(), key.as_ptr())
> }),
> })
> }
> diff --git a/rust/kernel/sync/lock.rs b/rust/kernel/sync/lock.rs
> index f6c34ca4d819..318ecb5a5916 100644
> --- a/rust/kernel/sync/lock.rs
> +++ b/rust/kernel/sync/lock.rs
> @@ -6,8 +6,8 @@
> //! spinlocks, raw spinlocks) to be provided with minimal effort.
>
> use super::LockClassKey;
> -use crate::{init::PinInit, pin_init, str::CStr, types::Opaque, types::ScopeGuard};
> -use core::{cell::UnsafeCell, marker::PhantomData, marker::PhantomPinned};
> +use crate::{init::PinInit, pin_init, types::Opaque, types::ScopeGuard};
> +use core::{cell::UnsafeCell, ffi::CStr, marker::PhantomData, marker::PhantomPinned};
> use macros::pin_data;
>
> pub mod mutex;
> @@ -113,7 +113,7 @@ pub fn new(t: T, name: &'static CStr, key: &'static LockClassKey) -> impl PinIni
> // SAFETY: `slot` is valid while the closure is called and both `name` and `key` have
> // static lifetimes so they live indefinitely.
> state <- Opaque::ffi_init(|slot| unsafe {
> - B::init(slot, name.as_char_ptr(), key.as_ptr())
> + B::init(slot, name.as_ptr(), key.as_ptr())
> }),
> })
> }
> diff --git a/rust/kernel/workqueue.rs b/rust/kernel/workqueue.rs
> index 553a5cba2adc..a6418873e82e 100644
> --- a/rust/kernel/workqueue.rs
> +++ b/rust/kernel/workqueue.rs
> @@ -380,7 +380,7 @@ pub fn new(name: &'static CStr, key: &'static LockClassKey) -> impl PinInit<Self
> slot,
> Some(T::Pointer::run),
> false,
> - name.as_char_ptr(),
> + name.as_ptr(),
> key.as_ptr(),
> )
> }
> diff --git a/scripts/rustdoc_test_gen.rs b/scripts/rustdoc_test_gen.rs
> index 5ebd42ae4a3f..339991ee6885 100644
> --- a/scripts/rustdoc_test_gen.rs
> +++ b/scripts/rustdoc_test_gen.rs
> @@ -172,7 +172,7 @@ pub extern "C" fn {kunit_name}(__kunit_test: *mut kernel::bindings::kunit) {{
> #[allow(unused)]
> macro_rules! assert {{
> ($cond:expr $(,)?) => {{{{
> - kernel::kunit_assert!("{kunit_name}", "{real_path}", __DOCTEST_ANCHOR - {line}, $cond);
> + kernel::kunit_assert!(c"{kunit_name}", c"{real_path}", __DOCTEST_ANCHOR - {line}, $cond);
> }}}}
> }}
>
> @@ -180,7 +180,7 @@ macro_rules! assert {{
> #[allow(unused)]
> macro_rules! assert_eq {{
> ($left:expr, $right:expr $(,)?) => {{{{
> - kernel::kunit_assert_eq!("{kunit_name}", "{real_path}", __DOCTEST_ANCHOR - {line}, $left, $right);
> + kernel::kunit_assert_eq!(c"{kunit_name}", c"{real_path}", __DOCTEST_ANCHOR - {line}, $left, $right);
> }}}}
> }}
>
I forgot to include the version history before sending the patch, sorry.
v1 -> v2:
- Do not remove `c_str` macro. While it's preferred to use C-string
literals, there are two cases where `c_str` is helpful:
- When working with macros, which already return a Rust string literal
(e.g. `stringify!`).
- When building macros, where we want to take a Rust string literal as an
argument (for caller's convenience), but still use it as a C-string
internally.
- Use Rust literals as arguments in macros (`new_mutex`, `new_condvar`,
`new_mutex`). Use the `c_str` macro to convert these literals to C-string
literals.
- Use `c_str` in kunit.rs for converting the output of `stringify!` to a
`CStr`.
- Remove `DerefMut` implementation for `CString`.
v2 -> v3:
- Fix the commit message.
- Remove redundant braces in `use`, when only one item is imported.
v3 -> v4:
- Provide the `CStrExt` trait with `display()` method, which returns a
`CStrDisplay` wrapper with `Display` implementation. This addresses
the lack of `Display` implementation for `core::ffi::CStr`.
- Provide `from_bytes_with_nul_unchecked_mut()` method in `CStrExt`,
which might be useful and is going to prevent manual, unsafe casts.
- Fix a typo (s/preffered/prefered/).
v4 -> v5:
- Keep the `test_cstr_display*` unit tests.
Powered by blists - more mailing lists